Principal vs. Principle

How to use "principal" and "principle" correctly

This is an entry on my list of Common Errors in English Usage. Visit the main page for direct links to additional entries.

Teachers have been lamely teaching their students since the dawn of time to memorize the meaning and spelling of principal by remembering that the school principal is supposedly your pal. What causes confusion is that principal has other uses as well: as an adjective meaning “main or most important” and as a noun with related meanings, including “a sum of money that draws interest” and “a leading performer”:

his principal objection to the treaty

the principal reason for my decision

a loan with a principal of $500

A principle is a rule or law—remember this by noting that like the word rule, it ends in –le. Remember the idiom “in principle” also.

a principle of good leadership

a woman of high principles

agree with him in principle but disagree about practical details

Related Resources

Common Errors in English Usage: Errors in diction and idiom commonly made by native speakers of English

List of Common Errors in English Usage (PDF): Printable version of the complete list

Common Grammar Errors: A list of common errors in grammar (topics like subject-verb agreement and parallelism) as distinct from usage

List of Common Errors in English Usage: PDF version

© 2006, 2008, and 2019 C. Brantley Collins, Jr.